1. Technical Field of the Invention
The present invention relates to the treatment of liquid media to insolubilize contaminating metallic impurities contained therein, and thus producing a nonleachable residue therefrom.
2. Description of the Prior Art
Industrial plants produce liquid effluents containing a large number of impurities, in particular metallic impurities which may be polluting, dangerous, and toxic for the environment. This is the case, for example, at nuclear power-generation plants, where liquid waste products may contain radioactive elements such as uranium, or, again, at phosphoric acid manufacturing plants, where the aqueous effluents therefrom contain abundant amounts of heavy metals.
The problem of elimination of these impurities is especially crucial, since environmental protection standards are becoming increasingly strict. On the one hand, it is not permitted to discharge effluents containing certain impurities; on the other, the residues produced following purification of these effluents must not pose any danger to the environment when subsequently stored.
These effluents must, therefore, satisfy precise standards. In particular, they must not be leachable, namely, it is imperative that they not release metallic impurities contained therein during lixiviation.